Cam-closing pivoted-jaw pliers having displaceable-half-nut actuator



p 1951 w. B. KRAMERyETAL 2,568,641

CAM-CLOSING, PIVOTED-JAW PLIERS HAVING DISPLACEABLE-HALF-NUT ACTUATOR Filed June 18, 1949 2 Sheets-Sheet 1 IN VEN TOR.

ep 1951 B. KRAMER ETAL 2,568,641

CAM-CLOS c, PIVOTED-JAW PLIERS HAVING DISPLACEABLE-HALF-NUT ACTUATOR 2 Sheets-Sheet 2 Filed June 1949 Patented Sept. 18, 1951 CAM-CLOSING PIVOTED-JAW PLIERS HAV- ING DISPLACEABLE-HALF-NUT ACTUATOR Walter B. Kramer and Thomas A. Moore, Afiton, M0.

Application June 18, 1949, Serial No. 99,894

2 Claims.

This invention relates to pliers.

The primary object of the invention is to provide a pair of pliers, the handles of which can be rotated independently of the gripping jaws to apply additional gripping pressure to the gripping jaws.

A further object of the invention resides in providing a plier whereby hand gripping pressure against the handles is not necessary in order to hold the gripping jaws in their gripping positions relative to each other.

A further object of the invention is to provide a plier wherein a gripping pressure of the gripping jaws cannot be released before the operating handles have been rotated with relation to the gripping jaws so as to allow pivotal movement of the operating handles.

A further object of the invention is to provide a plier which may be quickly and conveniently adjusted to grip parts or articles of various diameters.

A further object of the invention resides in providing a plier which is adjustable to grip parts of various shapes and diameters, and which may be locked without maintaining hand gripping pressure against the operating handles.

A still further object of the invention is to provide a plier to overcome certain practical objections to, and defects in pliers of the conventional types.

Other objects and advantages of the invention will be apparent from the following description.

In the accompanying drawings forming a part of this application, like charactersof reference denote similar parts throughout the several views.

Referring to the drawings:

Fig. 1 is a front end view of the pliers, the operating handles being shown also in dotted lines in a rotated position relative to the gripping jaws.

Fig. 2 is a side elevation of the pliers, the gripping jaws being shown in fully closed position.

Fig. 3 is a plan view of the pliers.

Fig. 4 is a side elevation of the pliers, the gripping jaws being shown as fully open.

Fig. 5 is a vertical sectional view taken on line 5-5 of Fig. 1.

Fig. 6 is a view partly in side elevation and partly in vertical sectional elevation, the operating handles being rotated anti-clockwise sufiicient to slightly separate the gripping ends of the gripping jaws to allow the handle screw-threads to be retracted from the screw-threaded handle support.

Fig. 7 is a vertical sectional view taken on line '|-I of Fig. 1.

Fig. 8 is a front elevation of the bell-shaped jaw operating pressure ring.

Fig. 9 is a vertical sectional view taken on line 9--9 of Fig. 1.

Fig. 10 is a front end view of one of the operating handles.

Fig. 11 is a view partly in side elevation and partly in sectional elevation of one of the operat ing handles.

The invention consists of a pair of rocking gripping jaws each carried by separate pivot pins supported by a connecting spacing member, a pair of operating handles each carried by separate pivot pins supported by a connecting spacing member slidably supported on a screwthreaded member projecting centrally from the spacing members carrying the gripping jaws, a floating bell-shaped pressure transmitting ring mounted centrally on the screw-threaded member and disposed between the inner ends of the gripping jaws and the inner ends of the operating handles and wherein the inner ends of the operating handles are screw-threaded to provide a separable tapped hole for engagement with and disengagement from the screw-threaded member.

Briefly, the pliers comprise a pair of like grip ping jaws l2, a yoked connecting member l3 for supporting the jaws, a stem designated, generally, as I4 projecting from the yoked member l3, 2. yoked connecting member 15 slidably mounted upon the stem M, a pair of like operating handles it pivotally supported by the last mentioned yoked member, and a bell-shaped ring I'l slidably mounted on the stem I 4 and engageable with both the gripping jaws and the operating handles, a coiled spring I8 interposed between the gripping jaws, and a coiled spring [9 interposed between the operating handles.

Each gripping jaw I2 is provided with a plane gripping surface 20 and an arcuately shaped serrated gripping surface 2 l. Each jaw l2 also includes a rear jaw portion 22 having a convexed inner face 23.

The yoked connecting member I3 is provided at each end with a bifurcated portion '24 to receive the rear portions 22 of the jaws l2. Each portion 22 of the jaws I2 is pivotally connected, at its respective bifurcated end portion 24- of the connecting member I3, by means of a pivot pin 25. The coiled spring 18 is interposed between the forward end portions of the rear jaw portions 22 to exert pressure to open the gripping jaWs l2 and the spring I8 is guided and located at its ends by pins 26 anchored in the jaw portions :22.

Th stem designated, generally, as H. is provided for a portion of its length with screwthreads 21 and the stem is screw-threadedly connected with and projects rearwardly from a screw-threaded opening 28 centrally of the yoked connecting member I3. The stem I4 is secured to the member I3 by means of a set screw 29 so as to lock the stem against rotary and longitudinal displacment relative to the connecting member I3. The rearmost end portion an of the stem M has no threads and is smooth and the stem I4 is provided at its free end with a flanged head 3 I.

The yoked connecting member I is slidably mounted on the non-screw-threaded end portion 30 of the stem and is provided at each end with a bifurcated portion 32 to receive the operating handles I6 a suitable distance back from the forward end portions thereof. Each operating handle I6 is pivotally connected at its respective bifurcated end portion 32 ,of the yoked connecting member I5 by means of'a pivot pin 33.

The inwardly projecting forward end or head portion 34 of the operating handles I6 are each provided with semi-cylindrical screw-threads 35,

as clearly shown in Fig. 10, which are adapted for engagement and disengagement with the screw-threads 2'! on the stem I l, as will be more clearly apparent hereinafter. The screw-threads 35 on the forward ends of the operating handles I6 are normall held in screw-threaded engagement with the screw-threads 21 on the stem I4 by means of the coiled spring I9 arranged between the handles IE and guided against displacement'by means of pins 36 carried by'the operating handles [6.

The outer fac of the forward end 34 of each operating handle I6 is inclined to provide a cam face 31 for normal engagement with the inner face 38 of the bell-shaped ring member I I, which member is slidably mounted upon the screwthreaded end portion 21 of the stem Id.

The outer face 39 of the bell-shaped ring member I1 is normally in engagement with the convexed inner surface 23 of the rearwardly projecting portions 22 of the gripping jaws I2 due tothe action of the coiled spring I8 arranged between the gripping jaws I2.

Operation Assuming the plier jaws I2 are locked in the gripping position, as shown in Fig. 1 and gripping an object designated 56, and it is desired to open the jaws I2, the operator turns the handles I6 counter-clockwise several turns which gradually and slightly opens the jaws I2 by action of the spring I8 sufficient to allow the operating handles I6 to be moved by hand gripping pressure toward each other sufiicient to disengage the handle head screw-threads 35 from engagement with the stem screw-threads 21 to allow the yoked handle connecting member I5 to be moved rearwardly upon the non-screw-threaded portion 30 of the stem I4 a suflicient distance to fully open the jaws I2, as clearly shown in Fig. 4 by action of the spring I'B.

- When it is desired to grip an object with the jaws I2, the operator grips the handles I6 to disengage the handle screw-threads 35 from the stem screw-threads 21, which allows the handles and member E5 to be moved forwardly to a position where the jaws I2 lightly grip the object .to be held between the jaws. If the light gripping action of the jaws I2 is not sufiicient to prevent the jaws I2 turning on the object being held, the operator turns the handles It in unison clockwise, causing the handle screw-threads 35to climb. for- 4 ward on the stem screw-threads 21. This action causes the cam faces 26 on the handles to exert additional pressure on the bell-shaped ring I! and the ring forces the convexed faced rear portions 22 of the jaws to be further spread apart causing additional gripping pressure to be applied to the object being held by the jaws I2. Anytime the jaws I2 firmly grip an object, hand pressure may be relieved on the operating handles I6, and the jaws l2 will still remain firmly gripped against the object between the jaws. It is believed clearly apparent that to apply additional gripping pressure to the gripping jaws I2, all that is necessary to do is to turn the handles I6 clockwise to secure the desired pressure effect. Due to the bell-shaped ring interposed between the rear ends of the jaws I and the cam surfaces at the forward ends of the handles, and the handle screw-threads engaging the stem screwthreads, it is impossible for the jaws to be released from the object until the handles are turned counter-clockwise sufficient for the hanv. dles to be actuated toward each other to release engagement of the handle screw-threads from the stem screw-threads so as to allow the connecting member I5 and the handles to be moved away from the jaws I2. This moving away action of the member I5 releases pressure against the ring I1, and thus releases ring pressure against the inner curved faces on the rear ends of the gripping jaws I2.

From the foregoing description, it is clearly apparent that any amount of pressure can be easily and quickly applied to the rear ends of the gripping jaws for transfer to the gripping ends of the jaws by merely turning, or rotating the handles I6 clockwise and without applying hand gripping pressure to the operating handles I6;

It is clearly apparent that gripping pressure is applied to the gripping jaws by rotation of the operating handles I6, and that this pressure is retained even though the hand is removed from the operating handles.

The many advantages of the herein described invention will readily suggest themselves to those skilled in the art to which it appertains.

It is to be understood that the form of the invention herein shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of the several parts involved may be resorted to, without departing from the spirit of the invention, or the scope of the appended claims.

What we claim is:

1. A plier comprising two like gripping jaws having rear convexed cam faces, a yoked member to which the jaws are pivotally connected, a'stationary stem projecting rearwardly from the yoked member having a screw-threaded forward end portion, a non-screw-threaded rear end portion and a head on the free end of the stem, a pair of operating handles having forward cam faces, inwardly projecting heads on the inner ends of the handles, matching internal screwthreads on said handle heads adapted for engagement with and disengagement from the stem screw-threads, a yoked member slidably mounted on the non-screw-threaded end of the aforesaid stem to which the operating handles are pivotally connected, a bell shaped ring having a central opening mounted for sliding movement on the screw-threaded end .of the stem, an expansion spring disposed between the operating. handles,

and an expansion spring interposed between the gripping jaws.

2. In a plier, the combination with a yoked member, a screw-thread member having a nonthreaded rear end portion projecting rearwardly from the yoked member, a second yoked member slidably and rotatably mounted on the nonthreaded end of the screw-threaded member, a pair of gripping jaws each having plane gripping surfaces and arcuately shaped serrated gripping surfaces, the rear end portions of the gripping jaws having convexed inner faces, means pivotally connecting the rear end portions of the gripping jaws to the ends of the first mentioned yoked member, a coiled expansion spring disposed between the rear end portions of the gripping jaws in advance of the first mentioned yoked member to urge the outer ends of the jaws toward each other, a bell-shaped member slidably mounted on the screw-threaded member having its outer face engageable with the inner convexed races of the rear end portions of the gripping member, a pair of operating handles pivotally connected with the ends of the second mentioned yoked member. outer cam faces on the forward ends of the operating handles engageable with the inner face of the bell-shaped member, matched screw-threads on the inner ends of the operating handles engageable with the screwthreaded member, and a coiled expansion. spring disposed between the operating handles to the rear of the second mentioned yoked member to urge the matched screw-threads into engagement with the screw-threaded member.

WALTER B. KRAMER. THOMAS A. MOORE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

